Project Summary Suicide is the 2nd leading cause of death among college students and suicidal ideation and suicide-related behaviors are a frequent presenting problem at college counseling centers (CCCs), which are overburdened. Studies show that some students respond rapidly to treatment, whereas others require considerably more resources. Evidence-based adaptive treatment strategies (ATSs) are needed to address this heterogeneity in responsivity and complexity. ATSs individualize treatment via decision rules specifying how the type and intensity of an intervention can be sequenced based on risk factors, response, or compliance. We are proposing a multisite study to investigate ATSs through a SMART (sequential, multiple assignment, randomized trial) to address suicidal risk in treatment-seeking college students. This multisite study (University of Nevada, Reno; Duke University, University of Oregon; Rutgers University), submitted in response to RFA- MH-18-700, Collaborative R01s for Clinical Trials, will enroll moderately to severely suicidal college students in the ?emerging adulthood? phase (ages 18-25) seeking services at CCCs. This SMART will have two stages of intervention. In the first stage, 700 participants from four CCCs will be randomized to 4-8 weeks of: 1) a suicide-focused treatment ? Collaborative Assessment and Management of Suicidality (CAMS) or 2) Treatment as Usual (TAU). Sufficient responders to either intervention will discontinue services/be stepped down. Non- responders will be re-randomized to one of two second-stage higher intensity/dosage intervention options for an additional 4-16 weeks: 1) CAMS (either continued or administered for the first time) or 2) Comprehensive Dialectical Behavior Therapy (DBT), which includes individual therapy, skills groups, and phone/text coaching for the clients and peer consultation for the therapists. The aims of this research project are to 1) compare the efficacy of the four ATSs in reducing students? suicidal ideation, non-suicidal self-injury, and suicide attempts; 2) evaluate whether, as hypothesized, a sequence that starts with a suicide-focused treatment approach (i.e., CAMS) is more effective in reducing suicidal risk than TAU; 3) determine whether, as hypothesized, a more comprehensive, suicide-focused approach (i.e., DBT) is more helpful as a second stage intervention for insufficient responders, relative to a less intensive suicide-focused approach (i.e., CAMS); 4) assess the mechanisms of change leading to reduced suicidal risk for each treatment; specifically, to evaluate suicidal cognitions as a mediator in CAMS and emotion regulation-based processes and use of skills as mediators in DBT; 5) examine baseline factors as predictors and/or moderators of treatment outcome; 6) evaluate the dissemination potential and cost effectiveness of using these ATSs within a CCC setting. This study will provide essential guidance to CCCs on how to best allocate limited resources to alleviate an increasing public health crisis.